001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.crypto.hash;
020    
021    import org.apache.shiro.util.ByteSource;
022    
023    /**
024     * A Cryptographic {@code Hash} represents a one-way conversion algorithm that transforms an input source to an
025     * underlying byte array.  Hex and Base64-encoding output of the hashed bytes are automatically supported by the
026     * inherited {@link #toHex() toHex()} and {@link #toBase64() toBase64()} methods.
027     * <p/>
028     * The bytes returned by the parent interface's {@link #getBytes() getBytes()} are the hashed value of the
029     * original input source, also known as the 'checksum' or 'digest'.
030     *
031     * @see Md2Hash
032     * @see Md5Hash
033     * @see Sha1Hash
034     * @see Sha256Hash
035     * @see Sha384Hash
036     * @see Sha512Hash
037     * @since 0.9
038     */
039    public interface Hash extends ByteSource {
040    
041        /**
042         * Returns the name of the algorithm used to hash the input source, for example, {@code SHA-256}, {@code MD5}, etc.
043         * <p/>
044         * The name is expected to be a {@link java.security.MessageDigest MessageDigest} algorithm name.
045         *
046         * @return the the name of the algorithm used to hash the input source, for example, {@code SHA-256}, {@code MD5}, etc.
047         * @since 1.1
048         */
049        String getAlgorithmName();
050    
051        /**
052         * Returns a salt used to compute the hash or {@code null} if no salt was used.
053         *
054         * @return a salt used to compute the hash or {@code null} if no salt was used.
055         * @since 1.2
056         */
057        ByteSource getSalt();
058    
059        /**
060         * Returns the number of hash iterations used to compute the hash.
061         *
062         * @return the number of hash iterations used to compute the hash.
063         * @since 1.2
064         */
065        int getIterations();
066    
067    }